Yes it does seem as if they are closely related but he did mention that his motive was an update of Steockler (which is D23 for 35mm?). In Edge of Darkess, Thornton said that he lowered the sodium sulfite to increase sharpness slightly in response to modern finer grain films. Then because modern thinner film soak up less developer he changed from borax to more active and alkaline bath B with Sodium Metaborate.

I'm only starting to learn some of this, so be gentle if I read wrongly...
Best regards,
James

Kodak D-23 (Published Formula Copyright by EK 1941) was one of the results of Kodak's motion picture developer R&D effort that started in the early 1900s. Kodak D-76 (1927) was an earlier result of this R&D effort. Many other manufacturers including Agfa and Ilford marketed formulations that were very similar to D-23 and D-76.

I started using D-23 to develop Ilford Pan F, Kodak Plus X, Tri-X and Panatomic-X 35mm film in the early 1950's. I quickly determined that I liked D-23 best diluted 3:1.

I also started using D-23 as a 2 bath developer (the Ansel Adams version) in the 1950s.